text:
Can I exercise rights related to a new rating for which a new license document has been issued before I actually go and collect it?
Trying to figure this one out but no guidance anywhere other than lots of opinions (which I'm actively seeking).
I'm planning a few flights in the coming days - just last month, I completed a checkride for the EASA competency based IR rating. The license has been issued and I can pick it up at the CAA office in person (don't ask) in one of the Baltic states. Thing is, I'm 1,5k km away where my domicile is and don't want to spend tons of cash and time to go get it.
Thus the question, can i legally fly IFR next week since I'm current and I have the rating even though the physical document I have in my hand does not list it? (The CAA website upon login does). Would this 'fly' in case of a ramp check after landing abroad?
Best,
private pilot

Well in North America you are supposed to have your docs on your person, same as a driver's license, so I would think you would get dinged for not having it in Europe as well.  You should be able to find the EASA regulation on it easily enough.

They didn't give you a temporary certificate??

Had the same issue, was not allowed to exercise my IR(R) until I had the silly piece of paper in my hand. Crazy rules as usual with aviation.

I think the wording you're looking for is in Part-FCL, FL045 - Obligation to carry and present documents (Emphasis mine)

A valid licence and a valid medical certificate shall always be carried by the pilot when exercising the privileges of the licence.

In my opinion, this indicates that you may not exercise the privileges of your license (ie, the IR) without having on you evidence of that rating. Whether a printout from the CAA website would do, is entirely open to opinion. I think the best advice would be to call them and ask them directly.


text:
SSDR as hour builder prior to CPL in the UK?
In the UK, to start CPL training, you need to meet the following requirements:

Hold a Private Pilot Licence (PPL)
Pass all ATPL Theoretical Knowledge examinations
Hold a Night Rating
Hold a Class 1 Aviation Medical
Have completed 150 hours of flight time as a pilot, including:

100 hours as Pilot In Command (PIC)
A Cross Country flight of at least 300nm with full stop landings at two different aerodromes.

My questions are:

What aircraft class must the 100 PIC hours be completed in?
If I already have a PPL(A) with a night rating, can I complete the remaining required hours in a Single Seat De-Regulated (SSDR) microlight (an example being the SD-1)?

After re-reading the CPL page on the CAA website...

Flight experience amassed in aeroplanes classified as Microlight (Aeroplanes), cannot be counted towards meeting any of the above requirements.

source: CAA CPL (See the "Experience requirements that must be met before the skill test" section).

source: Stack Exchange

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text:
Why do I often see bunches of medical helicopters hovering in clusters in various locations

As you can see in the screenshot there are hovering clusters of medical helicopters in multiple areas. I feel like I see hovering helicopter clusters every time I open the flightradar24 app. I couldn't find anything about this when I googled. Any ideas? Thanks!

Why do bank robbers rob banks? Because that's where the money is.
Why do airplanes cluster at airports? Because that's where the runways and terminals are.
Why do medevac helicopters cluster in certain locations? Because that's where the hospitals are. Hospitals large enough (busy enough) to have helicopter infrastructure are likely to be in dense urban areas, and dense urban areas are likely to have more than just one large hospital.
Helicopters clustering somewhere that isn't a hospital are likely retrieving patients from a mass casualty event like a pile-up on a highway.

That's how they decide where to build an airport, somebody looks around and says "Gee there sure are a lot of airplanes here, we should put in a runway!"

Exactly - they build hospitals near where helicopters roost.

It just seems really inefficient to keep the choppers up in the air doing nothing for so long

@taradevlin are you sure they are hovering, Pittsburgh is a lot bigger than it looks on the map. Or maybe their position is just not properly updated on flight radar.

@tara, I rather doubt that the medical helicopters are hovering. If there is a helicopter hovering it is almost certainly either a TV news crew or a police helicopter doing surveillance.

@taradevlin that website shows every aircraft with a working ADS-B transmitter. Those transmitters are turned on well before takeoff and turned off when the aircraft is shut down. So a helicopter sitting idle on the ground with the engine turning over, waiting for a call (or for takeoff clearance) will have the transmitter running.

@jwenting: That sounds like a key part of the answer to what the OP's really asking, that there seem to always be hovering medical helicopters.  The question already emphasizes "hovering" enough that your comment could pretty much be posted as an answer.

@PeterCordes possibly. I was on hotel internet when commenting, using a tablet screen, so not really suitable for writing longer things than a comment.

Also most "base of operatiojns" places (in many european, belgium, netherlands germany) countries for helicopters are not hospitals: hospitals are where patients go to and need good road connections.  Helicopters just need to be central, they are often used to bring personel, not transport patients; As such thy are often centrally at their own "spot" with its own team.

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text:
What is the minimum manpower required for A320 start up airline
Ideally on a A320 aircraft how many captains, first officers and cabin cre would be required for a start up airline accounting for 2 Management Captains, standby, training, sickness, leave, mandatory 8 days off.
Thanks MAS

Sounds a bit more like business related as opposed to aviation related.

@CarloFelicione is the business side of aviation off topic then?

It depends on the cancellation rate you wish to achieve and the schedule of the plane. At minimum 2 people.

If the FAA regulates it, I would accept it as aviation-related.

How many airplanes?  How many routes?  Way too many unknowns to answer...

The question is clear, and about aviation. The answer won't be opinion based. but competency based. Whoever thinks that starting an airline just requires an opinion and no expertise or research...Voting to keep open.

The FAA regs Part 121 apply to regularly scheduled carriers, and contain all the requirements to obtain an operating certificate. Most entities who want to get into this business hire one or more consultanta with experience in the certification process. Just the required manuals and documentation can rise to thousands of pages. Not for the faint of heart.


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How does the entertainment system in aircraft receive moving Map data?
How does the in-flight entertainment system inside an aircraft receive data for the moving map, like position, airspeed, origin and destination?
Is it connected to ADS-B receiver or it gets data from on board Avionics System?

Partially. As no relevant answer as well doesn't have same question related to ADS-B receiver.

Why would it have anything to do with ADS-B? ADS-B is a broadcast of information which goes from the aircraft to receiver stations on the ground. The aircraft already knows where it is (in order to send the ADS-B); why would they build ADS-B receivers in each seatback? Besides the fact that IFE moving maps have been around since long before ADS-B.

Not each seat but a single receiver which feeds the avionics , same data can be sent to  IFE.

The avionics would be fed by physical sensors directly, not ADS-B. ADS-B is not designed for that.


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What to do when an AD is published but your aircraft is nowhere near a maintenance facility?
If an Airworthiness Directive is published for your aircraft which makes it illegal to operate until complied, and your aircraft is sitting in the Alaskan wilderness with the closest facility hours away, what is the correct procedure? Would it be against the law to fly it directly to the facility? Would a technician have to travel to you? Any bush pilots have an answer? Thanks.

First thing you would do is study the compliance requirements of the AD.
Most ADs come with some kind of "fly-by" compliance period either by calendar date or hours/cycles. It's pretty unusual for an entire type or model to be grounded immediately.
But if that happened, you would examine the compliance procedure. If a mechanic is available to be flown to the location with the equipment necessary to perform the compliance procedure, you might decide it's cheapest and easiest to do that.
For example, if a fleet was grounded as of midnight this AM, and it required a detailed visual inspection, or even a Non Destructive Test of something like a control horn or some such that allowed some field performable procedure like Dye Penetrant, I might just have the mechanic flown to the site, do the procedure called for in the AD, sign off the inspection, and we're back in business.
If a mechanic wasn't available, or the compliance requirement needed the airplane to be flown back to a maintenance base, you would contact the FSDO for your region to apply for a ferry permit to take the plane to a maintenance base. The terms of the ferry permit will determine whether or not some check has to be done before flight, or whether a mechanic has to do it or just the pilot.
Immediate grounding ADs are generally avoided because they are so disruptive and result in a flood of ferry permit applications. Normally an analysis and risk assessment is performed to arrive at a compliance grace period that meets a mathematical risk probability threshold while giving the fleet as much flexibility as possible.


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wiring on commercial airlines
In reference to commercial aircraft ie: Boeing 700 series etc. Are there electrical wires running along the fuselage sides and under the windows where the passengers sit?

The wires run everywhere. Here is an example diagram from a 3D CAD - the yellow is the wiring. This is the A380, which has a total of ~500 km of wiring.

There is some wiring in the cabin, where the passengers sit.
However, most of the wires do not run through the sides of the passenger cabin. The preferred place to route them is under the floor and above the ceiling, in the plenum area, where it can be better organized.
Along the ceiling, you can see the wire harnesses:

Much of it comes together under the cabin and cockpit, in the avionics compartments, on the cargo deck level.

There are certainly a lot of wires in a commercial aircraft (many kilometres) and they are typically bundled into a number of wiring ‘harnesses’ or ‘looms’ that run throughout the aircraft.  Many of these are above the passengers’ ceiling or down in the cargo area.  There will doubtless be some wires that pass close to the windows.  The layout will be chosen to keep critical systems separate, minimise cable length and avoid areas where the cables could be damaged.


text:
Credit for a sports license
As a new CFII, I have a student who has about 250 hours in a Czech Sport plane, lots of cross-country time, etc. He also already has about 40 hours in a C172 going back 12 years.  Looking at the requirements for a PPL, how much of that SPL time will count?  Seems to me, once he's comfortable in our C172 and completes his night requirements, he's got all the other requirements??  Am I right?

was their instruction time from a CFI or a CFI-S?

Most of the hours count, assuming your student has already earned the SPL. From part 61.109(l):

The holder of a sport pilot certificate may credit flight training received from a flight instructor with a sport pilot rating toward the aeronautical experience requirements of this section if the following conditions are met:
(1) The flight training was accomplished in the same category and class of aircraft for which the rating is sought;
(2) The flight instructor with a sport pilot rating was authorized to provide the flight training; and
(3) The flight training included either -
(i) Training on areas of operation that are required for both a sport pilot certificate and a private pilot certificate; or
(ii) For airplanes with a $\text V^H$ greater than 87 knots CAS, training on the control and maneuvering of an airplane solely by reference to the flight instruments, including straight and level flight, turns, descents, climbs, use of radio aids, and ATC directives, provided the training was received from a flight instructor with a sport pilot rating who holds an endorsement required by § 61.412(c).

SPL students do not usually receive instrument training, and if they have the instrument hours only count if they were given in accordance with 61.109(l)(3)(ii). SPL students do not receive any night training so you will have to provide those. Finally, you will need to provide them with the required 3 hours of checkride preparation within two months of the checkride.
If your student received their previous training from a CFI instead of a CFI-S, then they can count everything regardless of whether they actually earned their SPL or not. It's still likely they did not receive instrument or night training, so you will still need to provide those.

All training was done with a CFII, appreciate the help, that’s about what I came up with also.


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Does anyone recognize the aircraft in this photo?
I saw this aircraft flying in the vicinity of Dulles International Airport today, while I was inside my car. I could not tell whether or not it was a turbine engine as I could not hear it.

It looks just like a De Havilland Dash 8 of some sort, likely a Q 400.

Thank you so much! It was driving me crazy. I believe you nailed it, though. We don't see many turbo-prop airliners around here near Dulles.  Usually just an occasional King Air or similar executive sized bird. The rest are mostly Boeing, Airbus and Bombardier jet-liners.


text:
Does the coriolis force have an effect on the direction in which an aircraft travels?
Suppose an aircraft is flying from Kenya (which lies on the equator) to UK (which lies in the northern hemisphere). Does the Coriolis force veer the aircraft to the right? Do pilots have to correct their flight route because of this?

Yes, the effect is there, and (auto-) pilots have to compensate for it, but the direct impact of the Coriolis force is insignificant compared to the impact of any wind forces.
This has been discussed on Physics SE: Coriolis force on bullet vs airplane
On the other hand side, the Coriolis force (seemingly) deflects moving air masses and causes the global wind patterns as we now them. Through the resulting wind forces on aircrafts, the Coriolis force has a very significant indirect impact on aircraft travel.

Though this answer is accurate in its main point, I think it is a stretch to say that the Coriolis force "drives" the wind system. Imagine a planet exactly like the Earth, with liquid water and an atmosphere. Now magically remove it to interstellar space but keep it spinning on its axis. An aircraft traveling on that planet would need to correct for the Coriolis force, but wind effects would be minimal compared to the real Earth. Wind is driven by uneven solar heating, not by the Coriolis effect.

Now, if your point is that the large-scale shape of the world's weather systems is heavily influenced by the Coriolis force, then I would agree with you. Without that force there would be no polar vortex, we would not have cyclonic and anticyclonic storm systems depending on northern vs southern hemisphere and so on.

@EricLippert You're definitely correct that uneven solar heating provides the energy for (at least most of) Earth's wind. On the other hand, though, if not for the Coriolis Effect, wouldn't we mostly just have relatively mild poleward winds at high altitudes and relatively mild wind toward the equator at lower altitudes? Jet streams and such wouldn't exist without the Coriolis Effect, would they?

@reirab: That's a good point. It's really hard to tease these things out because of course the Coriolis effect is simply the observation that the Earth spinning has consequences. Asking "what would happen if the Coriolis effect did not exist?" is tantamount to asking "what if the Earth did not spin?", in which case weather would be profoundly different because that uneven heating would stop being on a period of a day and start being on a period of a year.

@EricLippert Right. Either, "What would happen if Earth didn't spin?" or "What would happen if some magical force exactly opposed to the Coriolis Effect happened?" (Which would then presumably come with its own set of additional problems resulting from violating Conservation of Momentum and probably Conservation of Mass-Energy.)

@EricLippert reworded - hope you like it better!

@EricLippert What if the Earth didn't spin but a really powerful massless light source orbited around the Earth once per day?

@user253751: Well if it were in orbit then it wouldn't be massless, but I take your point. That's a really interesting question and I don't know the answer. It would be interesting to see a simulation of that.


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Why is the inlet cone shaped conical?
Why are inlet cones of a lot of aircrafts conical. I read that it has something to do with slowing down supersonic airflow entering inside the engine. Is this true? If so, can somebody please elaborate on it?
Also why does supersonic airflow have to be slowed down before entering the compressor/combustion chamber. Does it cause engine flameout if not slowed down?

Also I've noticed that  the inlet cones of supersonic aircrafts are more pointy than that of subsonic aircrafts. Why is this so?

I would venture to guess that on higher-speed aircraft, you get way more air going into the intake than you need, which is why you want the intakes to have a variable geometry. Alternatively you can sacrifice low-speed air intake volume to sustain higher-speed air volumes.

As Wikipedia explains it:

The main purpose of an inlet cone is to slow the flow of air from supersonic flight speed to a subsonic speed before it enters the engine. Except for scramjet engines, all airbreathing jet engines need subsonic airflow to operate properly, and require a diffuser to prevent supersonic airflow inside the engine. At supersonic flight speeds a conical shock wave, sloping rearwards, forms at the apex of the cone. Air passing through the conical shock wave (and subsequent reflections) slows to a low supersonic speed. The air then passes through a strong normal shock wave, within the diffuser passage, and exits at a subsonic velocity. The resulting intake system is more efficient (in terms of pressure recovery) than the much simpler pitot intake.

If the flow was supersonic inside the engine, it would not be able to maintain fuel burn.
The pointyness of supersonic jets' inlet cone is dictated by the distance from the tip of the cone to the engine inlet and the inlet diameter. Also, the shockwave must be kept at right location in relation to the engine inlet, so the location of the cone is adjustable (by computer)

The inlet cone is shaped so that the shock wave that forms on its apex is directed to the lip of the intake; this allows the intake to operate properly in supersonic flight. As speed increases, the shock wave becomes increasingly more oblique (the cone gets narrower). For higher flight speeds inlet cones are designed to move axially to control how the capture area varies with the duct internal throat area. For best intake operation this required area ratio gets bigger with increasing flight Mach number, hence the large inlet cone movement on the SR-71 which had to perform well from low speeds to Mach 3.2.

The engine in the first picture is not of a supersonic aircraft. It is a high bypass turbofan, and the cone in that engine has no other function but to serve as an aerodynamic form covering the end of the axel. The other picture (actually quite obviousy taken form the Wikipedia article I referenced above...) is a supersonic engine inlet cone of MiG-21MF
For the most interesting reading about supersonic engines, please see this Wikipedia article about the J58, an engineering marvel from more than sixty years ago. It still stands as one of, if not the most inspirational jet engine.
The article has a nice schliering photograph of what happens when the shocwave is not in the place it should be (NASA document ID: C-1955-37520, public domain):

Is the cone on the turbofan in the first photo really slowing down the air? It almost seems like it's an aerodynamic "cap" over the flat center of the fan.

No it is not @zymhan , as you stated it has no other function but to be as aerodynamic as possible. I'll ad that to my answer asap.


text:
Can a transonic airfoil have two shock waves?
I am currently running CFD cases on a transonic airfoil at Mach 0.75 and performing an angle-of-attack sweep to evaluate its performance. When I reached the angle of attack of 4.5 degrees (which I appreciate is very high for transonic flight, but tested nonetheless), a dual shock was formed on the suction side. Is this physically possible?
I understand how the suction-side flow may reaccelerate after a shock with favourable pressure gradient and possibly exceed sonic again, leading to a second shock, but wouldn't it just produce a single, stronger shock downstream?
I attached the two flowfields, colored by Mach number, with the first image representing the angle of attack of 4.5 and the second at 3.5 degrees.

Following jayS answer, I plotted the Cp for the two airfoils seen above, for comparison to the chart found.

I wouldn't say that 4.5° is "very high" in such absolute terms. It depends on the phase of flight and the manoeuvre being performed.

Yes, true, but we are talking about transonic flight conditions. The 4.5deg gave me a Cl of 0.79, Cd of 0.043 and a wing loading of 1170kg/m^2, which is quite high in my opinion. If my calculations are correct, it's the equivalent of doing a 1.5G banking turn on an A380 at cruise

Sure, I acknowledge that, what I would propose is that you somehow mention in in your question, for example by saying "I appreciate is very high for the given flight speed, but tested nonetheless". The current phrasing could be interpreted as you saying that 4.5 is always high.

Very Interesting results. I must say I have never before seen such a peculiar case. Yes, theoretically it seems possible to have this situation, but it's difficult to say if this is possible in reality or not. I found another similar behavior mentioned here:

One of the three aerofoils has dual shock.
It's difficult to say whether it's a physically correct situation or a mere artifact of CFD, especially without data on type of solver, type of simulation, numerical methods employed, mesh details etc. It would be advisable to simulate the same case in another code and see what results are seen.

Yes, I am currently busy finishing my dissertation, but intend on playing with more cases on different meshes. I have all the information on the solver, but I didn't want to overwhelm with CFD information, when the answer was possibly one of aeronautics alone. Yes, I will try this in another solver and report back within a week

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What is that wire on the picture?

I thought it was HF antenna  the What is the purpose of that?
What kind of nav aid use HF frequency?

It is, in fact, an HF antenna. Newer Herks may have HF antennae that aren’t that sort of long wire, but on older C-130’s, that is where they put them, and that is, in fact, what that is. And thus, closing as a duplicate is correct.

And want it's for?

Related

That won’t help

It is an antenna for a High Frequency communication radio (HF, as opposed to VHF or UHF or etc), and communication as opposed to navigation. It's not for any sort of navigation receiver, but rather for a radio somewhat similar to Ham Radio (although perhaps with higher power).

It's for Sense antenna in ADF actually

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text:
Where was the J-20 design stolen from?
Lets clear the Question Detalis
Once upon a time, I heard something like "China hacked X country and stole aircraft designs" and rest of the news were about an newer Chinese jet
Now, It looks somewhat like the F-22 Raptor
Now the last section (Video under here) was put as a joke
But admit it , even though it looks like an joke, It looks extremely the same ! (It also looks like J10)

Your title takes for granted that it was "stolen", while the body of the question does not. Which of the two?

Any answer to this question can only be speculation. China will never admit stealing plans and proving they did is virtually impossible.

Where was the J-20 design stolen from?

There are various unsubstantiated reports circulating which link the J-20 design to

Theft of F-35 engine design details
Theft of F-35 design data
Jailing of Chinese businessman Su Bin for espionage
Chinese National Pleads Guilty to Conspiring to Hack into U.S. Defense Contractors’ Systems to Steal Sensitive Military Information

A criminal complaint filed in 2014 and subsequent indictments filed in Los Angeles charged Su, a China-based businessman in the aviation and aerospace fields, for his role in the criminal conspiracy to steal military technical data, including data relating to the C-17 strategic transport aircraft and certain fighter jets produced for the U.S. military.

But overall, the suggestion that the J-20 airframe design was stolen is not well supported.

One theory states, that the design was taken from a videogame? Could that be true?

No.

That "Video game part" wasnt there, someone edited without knowing the fact that, that was an "joke"

When posting such questions you might want to give more context; who is everyone and where are they saying that it has been copied.
The J-20 is based on an earlier project called J-XX, dating back to the 1990s. It is very doubtful that it has been copied from a computer game, as the design process of a military aircraft cares little about the visual looks and more about the aerodynamics and performance. A computer game on the other hand cares nothing about these aspects, and only about how it looks.


text:
How strong someone should be in order to fly without "power steering"?
Planes these days use fly by wire systems while older ones had a mix of hydraulics with electronic assistance like the MD-11 (And maybe 737-800?).
But what would happen if you lost the electronic systems and you had to fly manually? I remember an incident of this happening in a MD-11 and pilots using raw muscle power to operate the flying surfaces (And using something like 10 kilos of force only to keep the yoke in place) or putting 10 kilos of force to the yoke constantly (My memory isnt exactly bad. It was a months ago)
So How much raw muscle power is needed to fly an MD-11 or an 737-800 without assistance for 10 minutes and then land? Through two pilots or as a single person.

It's not an answer, as you seem to be only asking about the MD-11 or 737, but the A-10 had "a mechanical system as a back up if hydraulics are lost. Flight without hydraulic power uses the manual reversion control system; pitch and yaw control engages automatically, roll control is pilot-selected. In manual reversion mode, the A-10 is sufficiently controllable under favorable conditions to return to base, though control forces are greater than normal."

Lots of airplanes used hydraulics only to provide boost to the existing mechanical controls, like car power steering.  Probably the first mass produced airplane to do this was the P-38L's hydraulically boosted ailerons.  It could actually outroll single engine fighters at high speed because full aileron was available with little effort by the pilot, whereas the FW190 guy had both hands on the stick trying to get max roll rate.  In that case if you lose the hydraulics you are back to manual controls, like losing your power steering.

The 737 has manual reversion (except on the rudder), allowing control without hydraulics, along with its predecessors the 707 and 727. These are the only Boeing jets designed this way.

@user71659 how strong someone must be to fly at near stall speeds (Because I think you need more muscle power to fight higher winds) with manual reversion?

Only small planes can fly without power actuation. The largest size airliner that can be flown manually would be about a B737, which actually has manual back-up for the elevator & ailerons as in this answer. The B737 uses a balance tab to assist in lowering the hinge moments during manual actuation.
In a much larger aeroplane like the DC-10, there is no practical amount of reducing hinge moments with servo tabs or other means, and flight control surfaces are deflected using hydraulic power only. This is schematically as follows:

When the pilot moves the stick, they deflect an input linkage which opens the servo valve of one or more hydraulic actuators. These then deflect, moving the output end, thereby closing the servo valve again. As long as there is enough total hydraulic pressure to overcome the aeroforce hinge moments, the actuator moves the control surface without any effort from the pilot required at all. In fact this would be so very light that artificial feel springs are mounted.
However, in some circumstances the actuators cannot overcome the control hinge moments, for instance due to:

Having to fight one of the other actuators, for instance because of a hardcover servo valve failure;
Hydraulic pressure loss in one or more of the actuators;
Mis-trim and high airspeed cause surface blow-down, as in several recent crashes.

Note that in this case, when the pilot pulls on the stick, they first deflect the servo valve until it hits the stop, and this now becomes the fixed hinge point of the input linkage. Further stick deflection results in direct manual surface deflection, against the hinge moments caused by the aeroforces and against oil still slushing around in the hydraulic system.
Like mentioned, in large aircraft with no measures to lighten hinge moments, the flight crew cannot practically control the flight path using manual force. A DC-10 did manage to actually land after total hydraulic failure by using differential engine thrust, not manual actuation.

The 707 and/or DC8 had cable and pulley flight controls.  I'm pretty sure the big four engine piston liners did as well.  The old flying boats certainly did.

One way to tell non-hydraulic flight controls at a glance is the existence of tabs and mass balances, and offset hinge lines (like a B-17's rudder).

What happens in practical terms is the depressuized surface will deflect under air loads until the servo valve bottoms out, then the surface will start pushing on the cable control circuit.  It might move about half way to full travel up or down before bottoming out the servo (the sag you see when the controls are unpowered on the ground).  In flight it would do the same thing, float down under airloads until it starts pushing on the control circuit as the servo bottoms out.  You'd be able to resist the last half of travel perhaps before the PCUs themselves get to their travel limits.

@JohnK No that is not what happens. The servo valve must “bottom out” first before the surface can start moving. The actuator itself does not bottom out before the surface stop. The surface will be at a position where the hinge moment equalises the internal resistance of the hydraulic circuit, wherever that is. You can push both ways and try to resist (which will be futile if designed as a fully hydraulic circuit).

@acpilot yes, same thing except that a cable can only transmit tension forces and you need a set of 2 of them for full control.

@Koyovis No.  The complex PCUs used on jets have one end of the piston connected to the servo valve linkage, not like your diagram.  The actuator always seeks to have the servo at null.  Input moves one way, the servo is displaced and PCU moves other way, restoring the servo to null at a new PCU position.  If the system is unpressurized, the surface will displace the PCU piston and it will move the servo valve link at the opposite end until it's at its limit, then it will try to push on the control circuit via the linkage.  The surface sags until the pitch feel unit resistance stops it.

You can't.  Most of these airplanes are flown with hydraulically powered control surfaces with no mechanical input possible from the cockpit flight controls.  The flight controls just operate servo control valves in the hydraulic actuators, like the bucket on a front end loader but a little fancier.  If it's FBW, the FBW system does the same thing at the actuators using torque motors operated by the FBW computers to drive the servo control valves.
There will be two, or three, hydraulic actuators driving each control surface.  The flight controls in the cockpit just control the extension/retraction of the actuators. Control feel in these airplane comes from spring devices in the control circuit to simulate "air loads".  There is no direct connection between the pilot and the dynamic forces acting on the control surface.  If you lose all of the hydraulic actuators, you lose the control surface.

There is no feedback from aeroforces - if there is hydraulic pressure. If no hydraulic pressure, there is feedback through the servo valve deadband.

Technically yes but you won't be able to effectively control the surface with whatever leverage you are able to apply mechanically to the PCU piston when you bottom out the servo valve input lever.

But I remember the incident of this happening in MD11 and the pilots flying the plane anyway.

This answer seems to ignore the MD-11 part of the question. Searching for "MD-11 fly-by-wire" finds several sources saying either that the MD-11 is not fly-by-wire (here, here) or that it has FBW only in some modes (here).

@T.J.Crowder OP might be referring to UA 232, a DC-10 suffering total hydraulic failure.

@Koyovis As I remember. They had to put 10 kilos of force to the yokes continiously without lifting their hands at all.

The MD 11 guys were not able to displace the flight controls.  They were controlling pitch and yaw with thrust alone.

@T.J.Crowder This answer also seems to be ignoring the 737 part of the question, which actually does have direct mechanical backup.

But remember the '37  is an ancient design.  It still has what amount to a Piper Super Cub trim system, with electric motors added.

@Koyovis After the engine failure, UA 232 was controlled solely by differential throttle. Part of their problem was the fact that the initial failure happened while the aircraft was making a right turn, leaving the rudder was deflected slightly to one side; they had to fight that steering force the whole way because they were unable to move the control surfaces without hydraulics. Their flight path has a few loops in it where they basically drifted off course and decided it was easier to go with the rudder and turn all the way around to the right than to fight it by turning left.

As a complement information to Koyovis answer, please note
On large airplanes, it is rather a  « servo tab » that will do the job you are asking for, in case of hydraulic failure rather than assisting the normal force that moves the elevator, it becomes the sole force that makes the elevator move. Therefore during normal flight it acts like a balance tab, in case of failure it becomes the sole active force. Like the balance tab, the servo tab moves in the opposite direction of the flight control’s trailing edge.
Please refer to the following website:
https://www.flight-mechanic.com/flight-controls-tabs/

Servo tab can be a mechanism, it means that the pilot deflects the tab only, which then deflects the surface. A balance tab is mechanically geared to the surface, pilot deflects the surface directly and the balance tab moves as a result of surface deflection.


text:
How willingly does US Military sell fuel?
Okay. I somehow (Either through a emergency or because I "miscalculated" fuel burn) landed on a US military airfield in a semi rural place in a state in US mainland without a airport pretty nearby
How willing would they give fuel? How much would they charge?

Comments are not for extended discussion; this conversation has been moved to chat.

The military doesn't "sell" fuel to civilian airplanes.
If you declare an emergency, USAF bases may be called on to provide for emergency landings. The fun begins afterwards, when you may or may not be detained and questioned. And later, they'll look for the best way to get you and your plane off their base, which may or may not involve refueling it. Only a few military planes (mostly basic trainers) run on 100LL, so rather than having the fuel brought in, some private pilots just got their plane towed off the base.
Then, you will be charged (billed) for the expenses. These are not limited to the cost of fuel (and delivering it to the base), but may include a number of other costs, including labor, and even a landing fee. It's not going to make financial sense, and it's going to delay you a lot.
If your reason for an emergency was unconvincing, you better hope it's a bill and not a court case, as the US military has an entire corps of lawyers, the JAG, who aren't paid by the hour. A few years ago, an unnecessary emergency landing at a military base ended in a fine for the pilot despite multiple mitigating circumstances.
For context, examining whether a pilot had sufficient reason to declare an emergency, much less suing them, is very uncommon in the aviation world. It's his diverting to a military base that led to such an unfriendly reception. As always, YMMV - there are just as many stories of very friendly receptions at military bases, mostly from the 1990s.
Just don't think of them as a backup gas station. The purpose of emergency landings is to save your life, not your trip.


text:
Why Buy A C182/172 Instead Of An C180/170?
So a thought came to my mind which covers not only Cessna planes but all others.
The Taildraggers need a little bit less runway becayse AOA on takeoff is good and that AOA eliminates the need of flaps on takeoff. This isnt so important anymore because most people live near to an airstrip unless they live in remote places.
They operate better in pale dirt runways because taildragger landing gear gets pressure from the weight of the engines etc. This is again not much needed because decently sized airstrips arent that rare and Cessna's dont need much landing distance anyway plus nobody lands on top of an mountain.
So why buy an inferior tricycle plane? Comfort? Because its so hard to operate and tractor tyred plane?
Thats exactly why I hate C172. Make an short range prop plane and add a tricycle gear? Which crazy person got that idea?

Strongly disagree with your statements re decently-sized airstrips, landing on top of mountains, &c.  (OK, not actually on top of them, but often on rather small strips within them :-))

I would have to ask: If a tricycle gear plane is "inferior", why are all modern commercial airliners built on tricycle gear? Additionally, you list benefits for tail-draggers, then state that those benefits aren't really necessary for "most" people, which contradicts your assertion that tricycle gear are "inferior". I'm quite confused, maybe you could reword this to make it more clear.

@FreeMan the airliners these days dont need rough field capacities and preventing the ground loops etc in a multiton airliner on a strong crosswind conditions would be impossible with the airline forcing the pilots to keep the schedule. Please edit my question.

@FreeMan by listing the pros and telling the not so needed I wanted to say why buy an M9 Bayonet which is easy to use and more recent instead of buying an old Swiss Knife that is more of an multitool that has more functions that arent much needed but can become handy which makes it an all around good and better knife.

Let us continue this discussion in chat.

So why buy an inferior tricycle plane?

Because the center of gravity is in front of the main gear, not behind.
Because you have better vision out the front while taxiing—no S-taxiing.
Because if you touch down with your heading not aligned with your direction of travel, the natural tendency of the airplane will be to straighten out, not to swap ends.
Because taxiing in a substantial crosswind is much easier.
Because when you go to sell the airplane, the pool of potential buyers is far larger than the pool that has a tail-wheel endorsement.

And it's much harder to flip it up on its nose and have a prop strike, compared to a tail dragger.

@CrossRoads: Though it can be done.  One of my partners managed to bend the prop on our Cherokee.

Steering a taildragger on the ground in the speed range between touchdown and ~10MPH or so is a skill that has to be learned, because in that speed range a taildragger is strongly yaw-divergent and has to be actively managed with the rudder and tailwheel,  and/or the wheel brakes, at every moment.
The landing accident that occurs when the pilot fails to keep the plane under control in that speed range is called a ground loop (see youtube for videos) and is one of the most common ways that taildraggers get wrecked. Tricycle-geared planes are far easier to control on the ground because they are not yaw-divergent.

So the only reason is because the nose down landings and ground loops which becomes a typical thing on wind landings? I would love to see an plane with tyres on wingtips.

check out the rutan Quickie and Quickie II!

If you control a taildragger with brakes alone you will wear out a lot of brakes.  Steering with brakes at low speed is only required on larger taildraggers with locking/free castering tailwheels (like a Beech 18 or DC-3) that is free to caster while taxiing at low speed.  With a steerable tailwheel like most light ac have, you steer the tailwheel and only use brakes to help with the steering occasionally, and to stop.

With the main gear down in a 2-point (wheel) landing, do you steer a  C170 or 180 with the brakes or the rudder until you put the tail down?

Rudder, unless the crosswind is so severe or you swing so badly that you're starting to run out of rudder travel and you're not stopping the swing, then you give shot of brake.  On a Beech 18 or similar, you do use brakes to taxi with the wheel castering, and on takeoff lock the wheel straight and only use little shots of brake if necessary until the rudder starts to bite.  If you fly something like a Champ with mechanical heel brakes, you only use them to stop and to hold the plane during runup.

OK, got it, thank you.

Taildraggers can't take off shorter than tri-gears.  A tri-gear airplane can actually achieve high AOA at rotation than a tail dragger because they can actually reach a higher pitch angle before the tail skid touches the surface.
The only real advantage a taildragger has over a tri-gear is prop clearance and somewhat better rough field capability by not having a nose wheel (ski operations make this really apparent; they are brutal on nose gears), so it's definitely a preferred configuration operating from snow or gravel.
Also tailwheel airplanes are slightly faster, all else being equal, without the drag of a nosewheel.
In virtually every other way, tri-gears are superior.  Controlability while rolling and landing, level floor on the ground, visibility over the nose, etc.
This is the reason that the huge majority of airplanes are tricycle.

Nose gear pants can reduce a lot of the drag from the front wheel hanging down.

Yes but you'll still be slightly slower than the identical airplane with a tailwheel.

My plane was never made with a tailwheel tho. Just fixed gear with a nosewheel, or a retractable version, with a nosewheel.

I had a '68 Cardinal for a few years in the late 80s. Fabulous airplane, pretty much a baby Centurion.

I have a '73. Love it.


text:
What is this "No Hand Hold" thing in the P-51 Mustang cockpit?
Does Anybody remember Combat Flight Simulator WW2 Europe Series ?
In the P-51, there is a "something" with "No hand hold" text on top of it
What is that ?
Image source

It is part of the gyroscopic gun sight:

Source: WarRelics Forum
It is not a "hand hold" because you don't want to damage the sight by grabbing the scope to situate yourself in the cockpit (getting in/out) or otherwise pulling on it. Since it is aligned to your guns, you would want to avoid misaligning it.

I think it's an important point that the part gives the strong impression of being a handle, and is just in the right place when you need something to hold on. The handle-like shape, I assume, is caused by making it round to be non-hazardous when hit with the head.

@VolkerSiegel It also looks to be padded, but I've never encountered one in person to verify.

@VolkerSiegel So basically, a very bad piece of user experience design based on… Dunno.

Yes, based on bad luck, I would say. I do not see how it could be fixed, in a technical way.  But wait - it could indeed be fixed on a purely user experience design level! Just make it look very different. Basically camouflage the "handlelikeness".

Presumably the "no hand hold" message was added after quite a few sights had become misaligned. For UX, you could paint it to look spiky, or just cover it in black and yellow stripes.

Aren't military vehicles, particularly planes, generally quite liberally decorated with text like "don't step", "don't push" and the aforementioned "no hand hold"..?

You'll see these in general aviation planes, too. Here's a Grumman AA5B cockpit.

It's Mk14 lead computing gyro gunsight.  Designed by the Brits, and credited with increased accuracy / higher kill ratio (it took a lot of the guessing out of shooting).  The padded part with "No hand hold" stenciled on it, was in fact padded to protect the pilots face / head from impact during a crash or crash landing.  The Mustang did not have modern inertia reals on the shoulder straps (they could be locked up manually by the pilot).


text:
How Cabin Pressures Are Selected?
The pilot puts the cruise altitude to the FMC and the plane auto adjusts the cabin pressure. I know that but I once heard the cabin pressure is set to three thousand feet.
Is it true? Why is the cabin pressure set to 3000 feet? How does plane designers of Boeing/Airbus/Bombardier etc. choose which altitude the cabin pressure will be set to?

Which aircraft are you talking about?

I'm not sure where you got the 3000 feet from, I think most cabin pressures are 6000-8000 feet.

@Bianfable the information comes from some a Quora answer which didn't specify aircraft neither I remember the value because I was super sleepy(Imagine mix of the Feminazi Tumblr, AskReddit and the stupidest of the Yahoo Answers and answering such questions making you famous) I have read some days ago. I am not looking for an specific aircraft anyway. I am just asking how aircraft designers choose what pressure the airplane use for cabin pressurization.

@DeltaOscarUniform OK, I thought you were talking about one specific aircraft because you mentioned automatic setting via the FMC. This is certainly not the case for all aircraft. A Boeing 737 still has the old school manual dial on the overhead panel.

@Bianfable actually that part is written here https://aviation.stackexchange.com/questions/45659/at-which-point-does-an-airliner-start-to-pressurize-depressurize-the-cabin .

Related: Do people get less airsick if cabin pressure is at 6000 ft.?

How do manufacturers select the cabin pressure?
In principle, the optimal cabin pressure for people on board of an aircraft
would be sea level pressure. However, this would create very large pressure
differentials between the inside of the aircraft and the outside at high
altitudes, which puts a lot of stress on the fuselage. One could build an
aircraft that can withstand these pressure differentials, but this would make
the aircraft very heavy, something that is not generally desirable when
designing an aircraft. It would also require a lot of bleed air from the engines reducing available thrust. That is why the cabin pressure is typically lowered
when climbing to cruise altitude.
How much the pressure needs to be lowered depends on the maximum pressure
differential allowed between inside and outside. Newer aircraft designs
using carbon composite materials like the Boeing 787 Dreamliner or the Airbus
A350 can withstand higher pressure differentials and thus allow a higher
cabin pressure (lower equivalent cabin altitude) than older aircraft at the
same cruise altitude (see also: Do people get less airsick if cabin pressure is at 6000 ft.?).
The cabin altitude must not exceed 8,000 ft at maximum operating altitude on a commercial aircraft.
To make sure that the pressure differential does not limit the maximum altitude
an aircraft can climb to, the fuselage should be designed strong enough to
maintain at least this cabin pressure at the aircraft's service ceiling.
What do pilots select?
The pressurization systems on modern aircraft are largely automatized. The
system only needs to know the cruise altitude and the landing elevation. From
the cruise altitude it can calculate the target cabin altitude for the climb
and cruise segments, which keeps the pressure differential below the maximum
allowed value. From the landing elevation it can calculate the outside
pressure at the destination airport and then start to approach this pressure
during the descent.
On a Boeing 737 these two values have to be selected manually by the pilots on
the overhead panel using the dials below FLT ALT and LAND ALT:

(source: http://www.b737.org.uk/pressurisation.htm)
You can also see a switch to the right (currently set to AUTO), which puts the
system into automatic mode (it is also possible to control cabin pressure
manually, but that is out of scope for this question).
On most modern aircraft however, the flight management system (FMS) will
automatically pass on the two required values to the pressurization system.
Assuming the system is in automatic mode, no pilot input is necessary.

As a generic answer, the only setting the crew inputs in most pressurization systems is the destination field elevation. This determines the pressure schedule on descent, and the system will use a cabin altitude descent rate that will put the pressure differential to near zero, usually slightly positive (that is, a hundred feet or so below field elevation) upon landing before the outflow valves are opened fully to vent the cabin to atmosphere.
So if the crew sets the field elevation at 3000 ft, the system will use a pressure differential reduction schedule on descent that gets the pressure hull close to zero differential when at 3000 ft, so there is minimum effect on people when the system goes into dump mode to vent the cabin.


text:
Do you need "Travel Visas" for "Cross-Intercountry" flights?
Now, everyone knows basic "Cross-Country" plannings that every pilot did through their PPL careers
But what about "cross-intercountry" planning ?
Now, lets say you have an C208B Grand Caravan Amphibian and you will go to the London International from the Atatürk airport through great circle route
You will need to stop for some "basic check" and fuel refills across the way
From different countries
But what is needed to land these airpots ? Do you need visas or something like that or you simply make an flight plan and inform the airports one by one ?
Or what if your engine goes dead and you need an emergency landing and you must stay at a random country for a few days or weeks ?
Or best of all, you land at an airport for an refill and take some souvenirs, would that be legal ? (If its too broad, answer for the laws of the countries on the great circle route)
Duplicate ?
My question addresses what would happen if the C208BGCA failed and what would happen if I had to stay in a country for a week or take some souvenirs there

A “cross-intercountry” flight is normally called an international flight. And yes, you need to research the aviation and immigration laws that apply to each country (or use an international flight planning service to help). Whether you need a visa somewhere will also depend on your nationality.

The very simple answer here is "yes".  There's no magic exception to visa regulations for "people piloting planes".  (Unfortunately!)


text:
How its like to fly an big back airliner with an sidestick ? How sensitive is the "joystick"?
Edited because it was "unclear"
Now Airbus uses sidesticks as control inputs
It looks weird for me because a tiny movement in the joystick would make a big movement and "joystick sensivity" would be extremely big and these things aren't needed for "Baby Got Back" airliners
So Why Airbus uses a joystick that has great "joystick sensitivy" ? Shouldn't sidesticks be reserved for tiny airplanes like Cirrus and F4E Phantom II ? (Whenever I see an regular F4 I laugh my ass off, Who would design a FIGHTER Bomber without an cannon ?)

"Is it comfortable?" is opinion-based. Please do not look for opinions here, you might want to try our chat for those.

Possible duplicate of Sidestick vs. Yoke

As long as the control surfaces are hydraulically actuated (so you don't need to exert a large force on the cockpit controls), what does it matter what the size of the aircraft is? The size of the pilot seems to matter more.

This question sounds awfully like, "joysticks are too sensitive, and yokes are better. Am I right?"  By stating that joysticks have great sensitivity and joysticks "aren't needed" for larger airliners you're presuming the answer in your question, forcing us to either tell you you've completely misunderstood things or just say, "yes, you're right".  A better question would just ask why side sticks exist or whether they're too sensitive, although the latter would be very opinion-based.  Do you want to learn or do you just want someone to agree or argue with you?

I Just want to know how sensitive sidesticks are

A side stick that can deflect 40 degrees is exactly as sensitive as a stick that can deflect 40 degrees.

Pilots fly big back airliners with a side stick very well. They also fly F-16s with a side stick very well.
As Airbus put it in an article in Flight Magazine: If side sticks were the norm and it would be proposed putting a big stick in front of the seat, making it hard to get in and partially blocking view of the instruments, pilots would protest".
All airliners have hydraulically deflected control surfaces, they don't need to physically overcome the airforces anymore. Their control stick can take any convenient shape,

Why not make an glass yoke ? (A super strong glass that wont crack in landing)

@JonathanIrons Answer that question yourself by holding a clear glass bottle between your face and your screen while writing a reply to this comment.

"Why not make an glass yoke?": What problem is it supposed to solve?


text:
How strong must someone be to open the door of a C182 and bail out?
Opening the door of a business jet seems easy. You depressurize the cabin then just open the "handle" and kick it down.
But what about the main door used to get out of the cockpit in an aircraft such as a Cessna Skylane? Assume a situation of 100 knots, flaps at 30°.
In such a situation, the door would act as a parachute and fighting 100 knots of wind doesn't seem easy. (Although opening the window would help a little bit.)
Could an average American (fat but not totally obese) do it?

Which door? The hatches on wings or the main door? Hatches will be opened inside, so also pressure will keep them in place, but main door open outside, so it is not the pressure that take them looked, but bolts and looks.

The main one to get into the cockpit.

@GiacomoCatenazzi the idea came from the movies where the protoganist just opens the door of a private plane and jumps away with a parachute leaving the porotgatinst to die etc.

Skydiving planes either don't install the door prior to flight, or have a garage door type system where it lifts up into the aircraft. Opening a Skyhawk door in flight isn't that hard and you don't have to be fat to do it. It's actually pretty easy if you side slip. The doors will actually pop open by themselves if not latched (ask me how I know).

@RonBeyer good answer. Also lets not forget this particular skydiver plane that opens outwards https://www.youtube.com/watch?v=7p6hqMnsLFY (Side section is thin compared to sideways door but whatever.).

The accident in that video happened not far from where I live. Everybody in that mid air collision survived, even the pilot who was able to bail out.

What does this have to do with emergency procedures?

@aCVn got to open door to bail out?

" the door would act as a parachute"  No, the door acts like a giant wedge and the wind tries to push it closed, just like a car.  In my Cessna Cardinal, which has a longer door than  a 172 or 182, the door can only be pushed open about 4" at the back.
Go driving, and see if you can push your car door open. Then try it on the highway.
I would think a C182 with flaps at 30 degrees would be doing less than 100 knots, 30 knots is used for takeoff and landing, when the plane would be going slower.

Wouldn't full fuel MTOW takeoff require higher airspeed and thus highen the stall speed?

What's that have to do with opening the door while flying?

simple. more weight the higher stall speed and the higher stall speed means you will have to  fly faster which means you will have to fight with more higher winds.

http://kirtlandflightcenter.org/wp-content/uploads/C182-POH.pdf  page ii, Flaps down, power off stall speed = 50 knots.  Independent of wind. Airborne wind only affects ground speed.  Higher weight just means a longer ground run to get to flying speed.


text:
How do you disable plane AI when the plane goes crazy?
This came to my mind when I learned 737 MAX crash was caused by the AOA indicators giving faulty info to the AI which crashed the plane.
So how do you completely disable the flight computer when it starts to control the plane but putting pressure on yoke or forcing the trim wheels dont solve anything? How do you remove the circuit breakers on a Boeing or a Airbus?
Altough this question seems like just another override the AI question. What I really want to know is how do I COMPLETELY disable the flight AI. It caused accidents when it happened in test flights but Id like to take a risk.

@ymb1 then I'd like to see an answer telling how to disable all of them

As I understand it, the flight control computers (which are not AI) on an Airbus are an integral part of the control system. If you completely disabled them you'd have no control at all. In that instance your question makes no sense. I think the same is true for some Boeing models, but I'm not sure.

Who said anything about AI?

@J.Hougaard: OP mentions AI three times, once in title and twice in last paragraph. No idea where they got that from, maybe the OP just means "software" in general?

@RedGrittyBrick Yeah my comment was directed toward OP, I can see now why that might not have been obvious

@ymb1 the definition of AI is (at least for me) "A computer software that does actions (Pitching the nose down or changing lanes) according to the inputs (Either AOA sensors or radars designed to see cars with the camera system to see lanes) without human interference" so yeah I think it can be counted as AI.

@Jonathan Irons - isn't that a definition of any data processing software that doesn't require human input?

Your definition (if we ignored the unnecessary requirement it be software) would call a mechanical thermostat (turns the heat on/off according to the temperature input without human interference), which dates back hundreds of years, AI.

TLDR: you follow the appropriate checklist for your aircraft.
For example:

How do you disable plane AI

There is no Artifical Intelligence (AI) in passenger transport aircraft.

Colloquially, the term "artificial intelligence" is used to describe machines that mimic "cognitive" functions that humans associate with other human minds, such as "learning" and "problem solving"

So far as I know, avionics systems pretty much have to follow a rigorously tested and designed but fairly traditional style of imperative and deterministic programming that does not involve the kinds of techniques that computer scientists might associate with AI, such as knowledge-based-systems, rule-based systems, fuzzy-logic, inference engines, etc.

737 MAX crash was caused by the AOA indicators giving faulty info to the AI which crashed the plane

There have been two crashes in which MCAS (not AI) is thought to have played a part. After the first crash, but before the second, the FAA issued an Airworthiness Directive (AD) that specified what action to take in the case of "uncommanded nose-down inputs".

Required by AD 2018-23-51
Runaway Stabilizer
  In the event of an uncommanded horizontal stabilizer trim movement,
  combined with any of the following potential effects or indications
  resulting from an erroneous Angle of Attack (AOA) input, the flight crew
  must comply with the Runaway Stabilizer procedure in the Operating
  Procedures chapter of this manual:

Continuous or intermittent stick shaker on the affected side only.
Minimum speed bar (red and black) on the affected side only.
Increasing nose down control forces.
IAS DISAGREE alert.
ALT DISAGREE alert.
AOA DISAGREE alert (if the option is installed).
FEEL DIFF PRESS light.
Autopilot may disengage.
Inability to engage autopilot.

...

Required by AD 2018-23-51
Runaway Stabilizer
  Disengage autopilot and control airplane pitch attitude with control column
  and main electric trim as required. If relaxing the column causes the trim to
  move, set stabilizer trim switches to CUTOUT. If runaway continues, hold
  the stabilizer trim wheel against rotation and trim the airplane manually.

...
It may be that the pilots in the second incident did not follow the revised checklist for this situation, or were not able to for some reason. More recent information suggests that following the runaway stabilizer
checklist can disable MCAS but also disables the ability to adjust trim "manually" using the thumbswitches on the control column. At some point there was a change
in the wiring/operation of the two STAB TRIM CUTOUT switches so that both have the same effect rather than being able to selectively disable automatic trim while
retaining the operation of the thumbswitches. This only leaves manual operation of the trim wheels - which can require a lot of strength in some circumstances.
The faulty AoA sensor and the actions of MCAS may have contributed to the accidents but there are other causative factors that need to be understood by anyone dealing with this situation. Battle over blame, BBC
Note that Boeing will now fit AoA disagreement indicators to 737s. I believe they also have issued MCAS revisions.

how do you completely disable the flight computer

There isn't one computer.
There are many computers. Usually there are different computers for each function and there are multiple redundant computers for the same function. If you want to disable a computer, you need to know what function you want to disable and know what effect that will have on everything else you are relying on. This is why there are checklists for pilots to follow for non-routine and for emergency situations.

I'd like to see an answer telling how to disable all of them

Modern passenger transport aircraft are very complex, there are many breakers, in multiple locations. Some of those locations are sometimes not in the cockpit.
It isn't possible to give, in this Q&A website, a complete list of all breaker locations for all passenger transport aircraft currently in service.

It caused accidents when it happened in test flights but Id like to take a risk.

People who like to take risks do not (or should not) pilot passenger transport aircraft like the 737.


text:
How exactly are checklists shared between the pilots?

Plane startups are shared between the crew

But how exactly? Does the captain do the startup and then ask the copilot if everything is correct? How exactly does it work? Is it aircraft specific or airline specific?

What is the source of that quote?  Its not FAA.  Is it SOP of a particular airline?

@abelenky I don't remember. All I remember is start ups are shared and there was an answer either here or in quora that dealt with this.

Typically, both pilots will set up "their" stuff as prescribed in the airline SOP's, and then the checklist will be called for.
At my airline, the captain has certain switches that he sets and certain systems that he checks -- generally things on his side of the overhead panel along with his flight instruments -- and the FO does likewise.  The FO performs the initial setup of the FMC, with both pilots checking what has been loaded (since some of the data comes in over a datalink).  Then, the captain briefs certain items, the clearance and routing are discussed, and then the captain calls for the checklist.  In flight, the flying pilot will call for the checklist (although if he's late in calling for it, the monitoring pilot my suggest, "are you ready for the Descent Checklist").
At my airline, the FO (or, in flight, the monitoring pilot) reads each item on the checklist, both pilots verify the switch or condition, and the captain responds.  Everything in the checklist is standardized, so the responses are predictable.  For instance, if the Before Takeoff checklist challenge is "Anti-ice" then the response might be "Off" or "Engine On, Wing Off" (since you don't operate on the ground with Wing anti-ice turned on in the 737).  But both pilots should be looking at the switch position to confirm that what is actually set (a) makes sense, given the conditions, and (b) matches what the Captain states.
Other operations will have some variation in this.  In another organization, the challenge "Altimeters" was answered "30.03, Pilot" followed by "30.03 Copilot" and then "30.03 Navigator".  Where I am now, we'd simply have both pilot check that the altimeters all match the ATIS setting, and the captain responds "30.03, set".  Either method works in a 2-pilot aircraft; with a Navigator and a Flight Engineer and a Loadmaster, crews in my old aircraft did things a little differently, in ways that made good sense in that operation.
So yes, the precise details of how all this is done are very aircraft- and airline-specific.


text:
Why were the Space Shuttle's elevons reversed, early in re-entry?
The veteran Space Shuttle commander Charlie Precourt writes, in the July 2022 issue of EAA's Sport Aviation, p. 38:

Another interesting reality about our flight controls was their
working essentially in reverse early in entry.  To effect a
right turn, we actually deflected the right elevon down which created
more drag on the right, yawing the vehicle right, increasing lift on
the left wing and causing roll to the right.  The downward deflected
right elevon was not causing roll to the left as it would in an
airplane.

In this situation, why wasn't the right elevon deflected up instead?  Wouldn't that also add drag, just like deflecting down?  Wouldn't that also somewhat reduce the right wing's lift, thereby encouraging the desired right roll?  Even in this regime (hypersonic, low air density, high angle of attack) there's some lift going on: he explicitly mentions the left wing's lift.  So some of the conventional behavior of wings and ailerons ought to still apply.

For an explanation let me first explain hypersonic flow a bit. In super- and hypersonic flow, when a body moves through a fluid what changes foremost is not speed but density. At the high angle of attack during re-entry, the flow over the upper side of the body is almost a vacuum and on the lower side the local density is much higher than the (very low) ambient density.
Therefore, any upward control surface deflection will make no difference as the control surface is moving essentially into a vacuum. For the downward moving control surface the picture is very different: the already denser flow gets compressed even more, producing a bit of lift and a lot of drag.
Early in re-entry, most of the lift is still provided by the centrifugal force of the orbital motion. The high angle of attack is only for braking and stability, and in the rarefied atmosphere little lift is produced by the wings. The high-g phase of descent is still to come.

1975 test of a Shuttle model in a helium wind tunnel (the glow from the shock structures is a result of electron-beam fluorescence | picture source)

Helium wind tunnel? Oooh la la

Is there a similar picture that plots the density field, instead of the pretty shock waves?

@CamilleGoudeseune: I wish there were - I found this pic by googling, but was unable to find anything about density.

For a cone at Mach 2, https://arxiv.org/pdf/2208.04280.pdf, Fig. 9, left column, shows the density field dropping to ambient, but hardly lower.  Mach 25 must be a different beast entirely.

@CamilleGoudeseune perhaps this computer generated image is helpful.  At re-entry altitude of around 100 km "ambient" density will not be much.

That image is helpful, but only insofar as it led me to search for CFD and density on nasa.gov.  I still haven't found plots of a density field, but I did learn that compressibility varies much more for large M, and that an "expansion fan" might apply here.

This observation is not unlike what F4 Phantom pilots experience using ailerons at higher AoA slow flight.
The downward elevon undoubtedly produces more (adverse yaw) drag.  The Shuttle is very low aspect ratio, meaning the elevons are much closer to the centerline.  In order to have the same roll torque as a higher aspect wing (ailerons further out), they must be larger.
As mentioned, extremely low air density$^2$ at re-entry altitude of around 100 km renders the upward elevon useless.
Primarily, at this point in flight, any resultant rolling into the downward elevon may not caused by increased lift on the opposite side as much as "dihedral effect" from its large vertical fin (and boxy fuselage).
So, the aerodynamic behavior of the Shuttle would be, overall, more drag$^1$ based until it reached denser atmosphere.  Until then, right elevon down was almost as good as right rudder.  There just isn't enough air available to form a higher pressure lifting "pocket" underneath the right wing.
$^1$ from wikimedia CFD computer generated image
$^2$ from source chart of atmospheric density vs altitude

Indicated airspeed at 300000 feet is almost nil.  But the Shuttle using wing warping to turn?  I never would have believed it.

Don't forget the dihedral effect from the swept wing (quarter-chord line of the delta wing is highly swept.)

@quietflyer the roll torques aerodynamicly are indeed the sum of all forces, including the wing.  What is interesting here, even at re- entry speeds, is that air density is close to 0 except in shockwave areas.  I think a modern Shuttle would feature twin rudders, more like a F-15.  In those high AoA situations, rudder is your friend.

A lengthy conversation has unfolded in chat, focussing mainly on how the side area of the fuselage may be affecting the roll torque developed during sideslip, and why-- read or join in at https://chat.stackexchange.com/rooms/141704/discussion-between-quiet-flyer-and-robert-digiovanni --

To effect a right turn, we actually deflected the right elevon down which created more drag on the right ... The downward deflected right elevon was not causing roll to the left as it would in an airplane.

The reason why deflecting the elevon down created a lot of drag but almost no additional lift as in a conventional subsonic airplane, lies in the particular behaviour of hypersonic aerodynamics.
At the hypersonic speeds typical of space vehicles reentry (Mach number much bigger than 5) air becomes an incandescent plasma mixture of ions O$^+$ and N$^+$ and  electrons and radios do not work anymore. It is a complicated chemical matter but, on the other hand, the aerodynamic behaviour becomes extremely simple. To explain subsonic and supersonic aerodynamics, at least a couple of books of hundreds of pages are needed. But to explain hypersonic aerodynamics a short chapter might be enough.
Indeed, at these extreme Mach numbers, the shock wave becomes so bent toward the body that it practically coincides with the body surface itself¹:

This is a huge simplification: if we follow one particle of air, it simply flies on a straight line until it bumps into the body; at that point it just bends its trajectory to follow the body surface:

The particles of air flowing beyond the surface of the body do not impact with it and they just keep on flying straight on: the "shadowed" surface do not experience any aerodynamic force and the air there just remains undisturbed: only the surface of the body being directly impacted by the air experiences an aerodynamic force.
That's the all story about hypersonic aerodynamics! Very simple indeed.
Since upon impact the particle has changed its speed (its speed perpendicular to the surface has become zero), then by Newton's second law ($F=ma$) all the particles of air bumping into the body generate a force ($N$ in the following picture) which is:

perpendicular to the body surface and;
with a value proportional to the mass flow times its perpendicular deceleration to zero:

For a flat plate the maths becomes really easy and simply returns:

$C_l= 2sin² α \times cosα$
$C_d= 2sin³α$

which look something like that ($C_l$ in red, $C_d$ in blue, my own work):

A couple of comments are definitely worth noting:

$C_l$ is not linear as it is instead at subsonic speeds.
$C_l$ starts at 0 at 0°, reaches a maximum and then decreases going again to 0 at 90°; the fact that it posseses a maximum has nothing to do with viscosity or stall or delta wing but only with the fact that at hypersonic speed the aerodynamic force is always perpendicular to the surface; there's no stall at hypersonic speeds.
For the same reasons, $C_d$ increases from 0 at 0° to 2 at 90° with an increase that, at least for small AoA, is cubic with AoA i.e. proportional to "³"; at subsonic speeds $C_d$ is simply constant at small AoA.
$C_{l_{max}}=0.77$ @ 54.7°; for a standard subsonic NACA 0012, $C_{l_{max}}$ is some 1.6 @ 22°, i.e. twice as much @ half AoA.
Obviously in reality at zero AoA $C_d$ is not zero but equals the drag due to viscosity $C_{d_0}$ and the whole plot can be simply shifted upward of $C_{d_0}$.
Maximum efficiency $L/D$ is between 6 and 7 while for the same NACA 0012 of before it is more than 20 i.e. three time as much.
Albeit being deduced for a flat plate, the two equations for $C_l$ and $C_d$ show a very good agreement with the aerodynamic characteristics of 3D slender bodies.

Now that we have learned the whole hypersonic aerodynamics (as promised in just one short chapter), how elevons worked on the space shuttle is easy to be understood:

first of all just forget about subsonic aerodynamics and any subsonic phenomenon related to moving surfaces; as seen, aerodynamics does not work in that way at hypersonic speed! There's no stall, lift is half at best and not linear with AoA, drag is bigger and so on.
Second of all, in order to present its belly to the atmosphere at reentry, the space shuttle maintained an AoA of 36 to 40°.

This is important: from the previous plot it can be seen that, at those AoA, lift and drag at hypersonic speeds have basically the same magnitude; the subsonic NACA 0012 of before at the same $C_l$ of 0.65 has a $C_d$ of 0.03 i.e. 20 times smaller! Furthermore, $C_l$ is already close to its maximum value: deflecting the moving surface downward does not have a big impact on the total $C_l$ (it might actually even decrease it) while it does modify $C_d$ a lot.
So, due to the peculiar aerodynamic characteristics at hypersonic speeds and due to the high AoA of the reentry phase, manoeuvring the space shuttle was achieved acting more upon its drag than its lift. And this finally explains why:

To effect a right turn, we actually deflected the right elevon down which created more drag on the right, yawing the vehicle right.

¹ all pictures from here

Now that's a really good answer. In my opinion, this is the best answer here +1.

@AdityaSharma: I also think that this is the best answer  But you know, sometimes is enough to be the first one and not the best one to win the competition here

Whenever you're generating lift with an airfoil, you're also generating drag. Deflecting an aileron up reduces the lift generated by the wing, and therefore, reduces induced drag. This causes the nose of an airplane to yaw in the opposite direction, a phenomenon called adverse yaw.
It's also true that the outside wing of an airplane in a turn generates slightly more lift than the inside one, because it's going faster through the air. This effect is normally so small it's not noticeable, but in certain situations (e.g. an incipient spin), this asymmetrical lift becomes a huge factor in the behavior of the airplane. In point of fact, the behavior of ailerons does reverse for a normal airplane in a spin, for much the same reason that it reverses for the Shuttle.

I agree with what you say about adverse yaw, but about your second reason: how much faster the outer wing is in comparison to the inner wing is directly proportional to the turn radius and wingspan. Span is constant, but the turn radius depends on TAS, and the space shuttle in this situation is operating at quite high TAS, probably so high that this effect becomes negligible.

Correction: Directly proportional to the wingspan, inversely proportional to the turn radius.


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How to describe turbulence and a plane nosediving in a script
I am a screenwriter whose script takes place aboard a plane. There is extreme turbulence during the flight. And at one point the plane nosedives and almost crashes. I want the instructions that the pilot gives to be as accurate as possible. I am including some excerpts from the script below. Can the pilots and flight crew among you provide some critiques of the script?
Also, I am looking for an aviation expert to provide some consulting on this low-budget film. It would probably be a few hours worth of conversation about the ins and outs of turbulence and plane crashes. Please let me know if you would be interested in being an expert for the film and getting screen credit.

Tangentially related: https://aviation.stackexchange.com/q/43453/7532

There are a few types of turbulence that can cause such a major reaction from an airplane the most likely being clear air turbulence (CAT) of which there are a few types.

Wake Turbulence:
This is the wingtip vortices caused by the pressure differential around the wing that come off an airplane and spiral down and away from an airplane. Generally, the larger an airplane gets, the more wake turbulence it generates because of the increased lift needed for the plane to fly. These vortices extend down and behind the airplane for a significant distance and can cause another airplane to lose control. There was an incident a few years ago between an A380 and a Challenger 604 where the Challenger crossed below the Airbus that resulted in such a situation. This one is probably the easiest explanation for your script as it can be very severe and the mechanism for generating it is a bit more simple than the weather-based turbulence types.
Jet Stream Turbulence
A lot of airplanes use the jet stream to get favourable tailwinds in order to get to their destination faster. However, there is a good risk of turbulence occurring due to the large wind differentials between different sections of the jet stream. The area of most turbulence when flying in the jet stream is just under and on the polar side of the jet stream core. Typically, the turbulence isn't as severe as what is described in your script, but it can occur (example).
Mountain Wave Turbulence
When wind passes over a mountain range perpendicularly and with a few other weather conditions, it can generate mountain wave turbulence which is a large oscillation in wind patterns that can extend for very long distances under the right conditions. This type of turbulence will have areas of major upflow and downflow which can change an airplanes altitude significantly. This type of turbulence can combine with jet stream turbulence to create even worse turbulence.

There are other types of turbulence that can cause severe turbulence like thunderstorms, but those are much easier to avoid as they are visible (not the turbulence, but the clouds associated with it).

Thanks for your detailed response. In my script, I don't really describe why the turbulence is occurring. It's a short film so I don't have a lot of time to get into specifics. Am I right in assuming that wake turbulence is caused by the presence of another aircraft? Also, would a plane nosediving be a possible consequence of this kind of turbulence?

@Hillary Yes, another aircraft would need to be present to generate that type of turbulence. And also yes, if wake turbulence is severe enough it can cause an airplane encountering it to nosedive.


text:
Helicopter induced velocity
I found this on one book I am now reading, and I dont uderstand how induced velocity is decreasing whyle climbing? And what is the difference between induced velocity and inflow velocity ?

I think the confusion here might be due to different frames of reference being used for the induced velocity and inflow velocity. Inflow velocity uses a fixed-body frame (meaning the coordinate system's origin is in the center of gravity of the helicopter), whereas induced velocity is defined within the earth's frame of reference.

...I dont uderstand how induced velocity is decreasing whyle climbing?

In the text it states: "The name 'induced' comes from the fact that the rotor forces this velocity into the air." When the helicopter is climbing, there is air flowing into the rotor already, without having to be sucked in and acelerated by the rotor.

And what is the difference between induced velocity and inflow velocity ?

Inflow velocity: the average velocity of all the air flowing into the rotor.
Induced velocity: the difference between average rotor inflow and outflow velocity.

So the term 'induced' refers to the thrust generation of the rotor. Picture below is Figure 2.5 from Principles Of Helicopter Aerodynamics, by J. Gordon Leishman, and illustrates momentum theory of a helicopter in the hover

The induced velocity $v_i$ can be seen in the pic, and when in the hover the induced velocity is identical to the inflow velocity: the rotor does all the work generating the airflow, creating negative pressure above the rotor.
When the helicopter is in a vertical climb however, air is flowing into the rotor already, and there is less induced velocity:
$$V_{in} = v_i + V_C$$ with:

$V_{in}$ = inflow velocity
$v_i$ = induced velocity
$V_c$ = climb speed.

I'd use picture 2.17 from the same book instead (axial climbing flight). I'd correct also the definition of induced velocity "the difference between average rotor inflow and outflow velocity" with a more correct $V_{\inf} - V_{in}$

@sophit then please do so, you're free to provide your own answers on this site.

The other answer to this question is already mine... I've only given a suggestion to improve your good answer, you're free to take it or reject it.

What a confusion!
The correct definitions are:

induced velocity $v_i$ denotes the speed (in m/s for example) of the air when going through the rotor; it normally varies on the rotor disk according to the flying conditions (thrust generated, flown manoeuvre, speed, density, ...). It is called induced since this velocity is induced by the rotor's presence.
inflow ratio $\lambda_i$ is simply the induced velocity adimensionalised via the rotating speed of the rotor $\lambda_i=v_i/ \omega R$. It is the same thing as the induced velocity (and sometimes it is indeed termed induced inflow velocity) but, as usual in the aerospace world, an adimensionalised quantity is preferred when making performance comparisons, just like $C_l$, $C_d$, Re, and so on.

That one increases while the other decreases is simply nonsense. The picture is also wrong since in reality the streamlines keep on contracting under the rotor (unless when very  close to the ground but that doesn't seem the case there).
If you want to learn something about helicopter I strongly suggest you the legendary Helicopter Aerodynamics by Raymond W. Prouty. Very easy to read, fluent and almost without equations.

My pictures are from Cyclic and collective book, by Shawn Coyle. I will try to find that book from Raymond W. Prouty

are you an aviation engineer, or something like that ? Do you have any other book to recommend ?

@CiricAleksandar: I'd have other books to recommend but they have more equations then words

"That one increases while the other decreases is simply nonsense." - If the inflow velocity ($V_{in}$) increases due to an increase in climb velocity ($V_c$), then induced velocity does indeed decrease, no?  After all, the question was asking about induced velocity ($v_i$) vs inflow velocity ($V_{in}$), not induced inflow ratio ($\lambda_i$).

@Philip: yep I might've been not that clear. My point is that "inflow" and "induced" are two terms often used interchangeably or even together as in "induced inflow velocity". To makes things even more complicated, "inflow" ratio is the adimensionalised "induced" velocity... I'll try to come up with a clearer answer. Thanks for pointing that out


text:
Why does a rectangular wing stall at the root first?
Study of countless aerodynamic questions and answers on this site has reshaped my understanding of both lift and and induced drag.
Questions like this: How does an aircraft form wake turbulence? have gone a long way to redirecting understanding about how induced drag works as well as what the wingtip vortices are, and most importantly, are not.
Study of the Aerodynamics for Naval Aviators text shows the various lift distribution and therefore stalling profiles of each wing planform.

Further reading will show the second attached image.

The ANA's explanation for why a rectangular wing stalls at the root first can be summed up as such: The rectangular wing planform has a strong wingtip vortex, this vortex causes strong downwash locally at the wing tip, and this downwash causes a relatively large induced angle of attack that culminates in the wing tip sections flying at a lower angle of attack than the rest of the wing, even without any washout.
My confusion stems from how extra downwash can be created at the wingtip. Assuming the wing has no washout / twist, the  coefficient of lift near the wingtip is lower than near the root, as is shown by the first image. If the lift coefficient is lower at the wingtip, how can the wing tip create more downwash than at the root?
Further contributing to this confusion is This question relating to elliptical wings. Peter's answer begins by stating that circulation (analogous to lift), can be interpreted as local lift coefficient times local chord.
How do these seemingly interfering explanations relate? Is there truly more downwash near the wingtip of a rectangular wing? Why does a rectangular wing have a lower lift coefficient at the tip than near the root? What about the shape of an "elliptical" wing allows a continuous lift coefficient to develop across the entire span?

The local lift is:
$l=c_l\, c\,q$
The local lift always goes to zero at the wingtip.  If the tip chord is non-zero, this means that the local lift coefficient at the tip will be zero.  If the tip airfoil had a pressure difference from top to bottom, that pressure would escape around the tip and equalize -- preventing any lift.
An elliptical wing has an elliptical chord distribution and also lift distribution.  So while the lift distribution goes to zero at the tip, so does the chord distribution.  These go together and an elliptical wing ends up with a constant $c_l$ lift coefficient distribution.
A rectangular wing has a constant chord.  But we know the lift must go to zero at the tip.  As it turns out, the lift coefficient will start out at a maximum at the root and will gradually fall off to zero at the tip - as shown by curve B from ANA.
The local lift coefficient is a measure of how hard that particular section is working.  For an elliptical wing, $c_l$ is constant -- and when the angle of attack is increased, all sections will reach the $c_{l,\mathrm{stall}}$ at the same time -- the whole wing will stall simultaneously.
For our rectangular wing, $c_l$ is greatest at the root, gradually decreasing to the tip.  Consequently, as angle of attack is increased, the root will reach $c_{l,\mathrm{stall}}$ first, while the tip is still far from stall.
The local lift can also be written in terms of circulation...
$l=c_l\, c\,q = \rho\,V_\infty\,\gamma$
We can write out the dynamic pressure $q=0.5\,\rho\,{V_\infty}^2$
$c_l\, c\,0.5\,\rho\,{V_\infty}^2 = \rho\,V_\infty\,\gamma$
And then cancel some terms...
$c_l\, c\,0.5\,V_\infty= \gamma$
or
$c_l\, c= \frac{2\,\gamma}{V_\infty}$
This doesn't reveal anything particularly profound -- other than we can work in terms of the local lift distribution $l$, the circulation distribution $\gamma$, or the product of lift coefficient and local chord $c_l\,c$.
In fact, you will also see people work in terms of the last one divided by the average chord.
$\frac{c_l\,c}{\bar{c}}$
Since all of these expressions are equal to the local lift multiplied or divided by some constant or another, they will all have the same shape on a graph -- with the y-axis scaled by the constant.

Excellent explanation for both the elliptical and rectangular wing and how they both must naturally achieve zero lift at the wing tip. It sounds like you are saying that the reduction of CL near the tips of the rectangular wing is aerodynamically caused by air pressure "bleeding over" from under the wing to the top of the wing. This sounds like a similar explanation to the excerpt from ANA I posted in the original question. So my secondary question is this: How does this all cause the stall to be delayed near the tips of the rectangular wing? Are the tips not at the same AOA as the root?

Basically, how does this exchange in pressure across the top and bottom of the wing tips cause an increase in stall AOA? Would adding additional pressure to the top of the wing not exacerbate the adverse pressure gradient that causes the stall in the first place?

I don't think anybody said anything about increasing stall AoA.  There might be some slight changes, but those get complicated.  Lets pretend for a moment that part of the wing will start stalling at 10deg.  In one case (rectangular wing) that happens inboard.  Since it starts in one place and spreads, it will happen gradually -- the airplane will feel mushy.  The tips will remain attached, which means the ailerons will be happy and roll control will be good.

In another case (elliptical), the stall happens across the whole wing at the same time.  Stall is more abrupt and has little warning.  You lose roll control at the same time.  In a third case (strong taper D or E), stall starts at the tip.  It is somewhat gradual -- the inboard wing with lots of area keeps lifting.  However, you lose roll control.  In addition, if you're in a turn, one tip will stall first, causing a strong rolling moment where that wing will 'fall out' from under you.  We can understand the implications of lift distribution on handling qualities without a lot of details.

When you talk about a 3D wing, it can be difficult to define the stall AoA.  Is it when the first sign of stall happens?  Is it when you reach CLmax?  The stall curve for a wing can be a sharp point, or it can be a gradual curve.  For some wings, it reaches CLmax and pretty much stays there for a long way, not really coming back down.  To figure out all the details, you need to get into quite a bit of 3D aerodynamic theory.  Start with lifting line theory, move to VLM theory.  It is complex and perhaps not worth your time when you can understand the end effect more readily.

Another option is to play with a tool like OpenVSP / VSPAERO -- or XFLR5 or AVL or Tornado etc.  These tools will show you the lift distribution for a given wing planform.  You can make changes to the wing and see what it does to the lift and lift coefficient distribution.

Is there truly more downwash near the wingtip of a rectangular wing?

Yes, but let's first clarify terms: Downwash is the downward movement of air added to the flow by the wing when creating lift. The downwash angle is proportional to the product of lift coefficient and chord. In potential flow theory it is proportional to circulation strength. But most important: Downwash occurs only behind the wing.
The flow ahead of the wing experiences upwash. Here, the effect is an induced angle of attack which is proportional to the same factors as downwash is.
Due to the high chord length near the tip, the rectangular wing shows a higher circulation strength near the tip, so downwash is more intense than in more tapered wings. But that is insignificant for your question which concerns stall. See below for more on this.

Why does a rectangular wing have a lower lift coefficient at the tip than near the root?

Tip effects. Since air is free to flow around the wingtip, pressure will equalize there. However, right inside of the wingtip the wing will already have a massive chord, so it will very effectively block this equalization of pressure. This means that the spanwise gradient of circulation is very steep at the wingtip of a rectangular wing. But that rapidly increasing circulation is caused by a lot of chord, so the local lift coefficient starts at zero at the wingtip and only slowly increases towards the root. Note that the rectangular wing has the least "full" lift coefficient distribution over span in the comparison sketch of the ANA.

What about the shape of an "elliptical" wing allows a continuous lift coefficient to develop across the entire span?

Here, chord and circulation move in lockstep over span, so their ratio is always equal. Since the lift coefficient links both, it can stay constant over span.
But what about stall AoA?
Stall is caused by flow separation which in turn is caused by steeper pressure gradients over chord. A positive lift coefficient means that pressure on the upper side of the wing will be lower than on the bottom side. This extra suction must be brought back to ambient pressure at the trailing edge, so a higher lift coefficient needs to be bought with a steeper pressure rise. Since a rectangular wing will have lower lift coefficients near the tip, the local pressure rise over chord is also less steep and flow separation is delayed in comparison with more inbound sections. Stall will happen first at the root.

ANA page 66 states that “ One of the important factors in this system is that a downward velocity is created at the aerodynamic center (w) which is one half the final downward velocity imparted to the airstream (2w)”. This goes on further to describe the reduction of CL at the wingtips to be caused by the local downwash increasing the induced AOA, which is what then causes the lower CL at the wingtips. Wingtip vortices adding to local downwash->more overall downwash at the wing tips than at the root->higher induced AOA at the wingtips-> lower section angle of attack-> wing tips stall later.

I’m wondering in the ANA may be either with an outdated understanding of the effects, or may just be written for someone to fly a plane who doesn’t need to understand the intimate engineering facets of why it flies. Its description of the topic doesn’t seem to make sense when it states that there is both more downwash and less overall lift at the tip of the rectangular wing. Your explanation seems to be more intuitive and reasonable.

@EquipmentOperator This view of downwash looks like someone only looked at the vortex and disregarded the translational flow. Then you get the highest up- and downwash at the AC, because that is where the core of the vortex is. In reality, you always have a superposition of rotational and translational flow and in effect the streamlines follow the contour of the wing surface. Which should obviously be correct since air does not enter into nor escape from the wing surface.


text:
Would a winglet be able to work in supersonic airflow?
Of course, there is a reason why existing supersonic airplane designs do not use winglets in the same way that an airliner wing uses winglets. I imagine the parasite/wave drag penalty from a winglet would far outweigh any potential lift-induced drag reduction for a supersonic aircraft.
But for the sake of a thought experiment, would a winglet affixed to an airplane in purely supersonic flow be able to carry out the improvement of spanwise lift that it does on a subsonic wing?
Since the air pressure signals cannot travel upstream in subsonic flow, does this mean tip effects are not present when supersonic? Or are they still very well present because the pressure doesn't have to travel upstream, rather across the flow stream in order to still create tip effects?

https://aviation.stackexchange.com/questions/42295/can-a-supersonic-aircraft-have-winglets

Sort of… I posted this question after reading that linked question and the responses as it didn’t seem to address the curiosity directly. In reference to this question, see my other question regarding tip effects on a piper wing: https://aviation.stackexchange.com/questions/100471/why-does-a-rectangular-wing-stall-at-the-root-first      I am trying to figure out if the mentioned equalization of pressure around the tip of a wing is capable of happening at supersonic speed, and then deduce from that answer whether a winglet could improve the situation the way it does in subsonic flow.

Oh, LOL, that I don't know. Sorry.